New plane from my FT Duster wing

I built the FT Duster when the design came out a few years ago.  My sons had a great time with the plane and they loved that it looked just like Dusty from the movie.  Since I live in Sweden, I don’t have access to Dollar Tree foamboard and instead the plane was built from 6mm Depron, covered with clear packing tape (which in hindsight was a bit unnecessary) and painted with orange hobby paint.

You can find a video I took from my FT Duster (before the vertical stabilizer mod) here.

My Duster had some modifications.  On the maiden I realized that the wings were a bit too small for the plane to carry the weight of a 2200mAh 3S battery.  Therefore I extended each wing with 100mm extra wingspan.  In combination with this I also made extensions to the horizontal stabilizer and later vertical stabilizer (picture taken before this mod) of about 50mm.  This made the plane fly quite good and it was a great plane for simple acro flying.  Another modification was that I made the wing attach under the plane using rubber bands instead of the original design where it sits inside the foam (this broke on the maiden flight as well).

After flying the Duster for some time, I thought it was a great plane, but it had a few drawbacks:

• A bit too small wing for its weight (therefore the extensions)
• Wing mounting that broke (therefore the rubber bands)
• A bit short-coupled which forced it to have quite large horizontal and vertical stabilizer
• The area at the bottom of the nose was not sturdy enough and had to be rebuilt too often after light crashes/hard landings (I did not use landing gear)
• The large hole in the top and bottom at the same place in the fuselage gave it a weak point there.
• The mounting of the servos in the rear fuselage often came off after light crashes/hard landings

Now, the new season started after winter.  I was about to take the plane out flying for the first time for the season.  The wind was a bit on the high side, and I was a bit rusty.  Shortly after launching the plane, I drove it straight into the ground at high speed.  The damage to the fuselage was too big to repair and the plane was dead.

But, the electronics and wing were still OK.  It was only the fuselage that finally gave up.  So let’s go back to the construction side of this hobby and build a new plane around those parts, and one that hopefully resolves at least some of the issues of the old plane.

So, this is what I came up with.  I don’t have a good name for it yet.  Any suggestions?

The plane is once-again built from 6mm depron, except for the stabilizers which is built from the closest thing we have to Dollar Tree foamboard here in Sweden.  The material is a bit heavier, and the paper doesn’t come off, but it is quite sturdy which makes it good for single-layer foils.  I’ve taped them with blue masking tape Experimental-airlines style.

Here are some specs of the new plane:

Overall length:  1090mm
Prop to leading edge of wing:  290mm
Leading edge of wing to leading edge of stabilizer: 570mm
All-up-weight: 780g
Wing: Regular duster wing, but extended 100mm on each side (outside of the ailerons)
Stabilizer control surface: 50mm
Stabilizer half span: 180mm
Stabilizer chord: 200 – 130mm tapering
Fuselage tube: 55mm square at the front, tapering to 35mm square at the back
Motor: 2217 1050kv Turnigy
ESC: 30A HobbyKing Red Brick
Prop: 9x6 APC
Battery: 3S 2200mAh

At first I thought that just using a square tube made from Depron would not be strong enough and that I would have to add some fuselage spar, but it surprised me how sturdy it actually is.  

The plane has two hatches on the right side to give access to the receiver and to the battery compartment with the ESC.  I am a bit concerned that the ESC will be too hot sitting that close to the battery and without cooling air, but we’ll see what happens…  Maybe some air holes in the hatch and on the other side would be a good idea.

The maiden flight show'd that this plane flies quite good.  It has good control authority in all axis, has plenty of power and is quite stable.  It does loops and rolls just fine.  It has, however, a lot of roll-to-yaw coupling which makes it hard to knifeedge.

Therefore I think I resolved some of the issues I set out to resolve, mainly that this plane is more stable than my Duster.  Regarding how well it survives hard landings, I don't know yet since I only did one maiden flight yet and the landing from that was quite smooth.